Push-over方法的理论与应用
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摘要
地震是对人类威胁最大的自然灾害之一,我国是全球大陆地震最集中的国家,地震强度和频度居世界各国大陆地震的首位。多年来人们一直致力于发展和完善抗震理论和工程措施,随着社会生产力水平的进步,近年来发生在国内外的几次大地震都呈现出伤亡人数小、经济损失大的特点。这一方面说明了经过多年的发展,工程抗震和相关学科已发展到了一个较高的水平,至少可以保证生命的安全,另一方面也指出了今后这一领域的努力方向,那就是在保证生命安全的前提下,同时保证财产的安全。在这种情况下,各国的政府、组织和研究人员开展了一系列的工作来迎接这一挑战,提出了“基于性能”这一概念,其基本目的是使工程建设具有可预计的抗震性能,帮助业主和设计者选择和实现针对各种建设项目的不同的性能水平。基于性能的抗震设计的实现方法主要体现为基于位移的设计,而初衷是建立一种大震下结构抗震性能的快速评估途径的push-over(推覆、推倒)方法,因为具有简便、直观、信息丰富的特点,随着90年代以后基于位移和基于性能的抗震设计等概念的提出和广为接受,得到了重视和发展。本文第一章首先讨论了基于性能、基于位移的抗震设计的一些基本问题以及目前国内外的现状,在此基础上,对push-over方法的起源、发展过程以及目前常用的能力谱法(CSM, ATC 40)和非线性静力法(NSP, FEMA 273)做了较为详细的介绍,针对其中的一些重要参数进行了讨论。
作为一种没有严密理论基础的抗震性能评价方法,push-over分析的准确性(可行性)基本上取决于它的计算结果是否能与其它可靠的方法所得到的结果一致或接近。在各种抗震试验中,振动台模型试验可以反映结构在特定地震激励下的动力特性甚至破坏机理,因此被广泛用于工程实践和研究。本文利用一个模型试验的结果,对push-over方法进行了对比研究。结合云南省少数民族民居的现代化结构体系和施工技术改建,试验对象是改进的整体预应力装配式板柱体系(IMS体系)。本文第二章首先介绍了这种结构体系自1977年引入我国以来所进行的主要研究工作,在此基础上为研究IMS体系在动、静力荷载作用下的动力特性及承载能力,进行了缩尺为1/2.7的模型试验。结合试验结果,进行了杆系模型的弹塑性动力时程分析,其中,尝试了一种新的钢筋混凝土构件非线性模型的模拟方法,即先用截面分析的方法得出钢筋混凝土构件的弯矩-曲率关系,然后将钢筋混凝土构件等效为由均质材料构成,通过引入某些假设将弯矩-曲率关系转化为弹塑性应力—应变关系曲线,从而间接地反映出构件的恢复力特性。这种方法的好处在于可以利用一些通用的有限元软件对钢筋混凝土杆件进行非线性分析。结合本模型的需要,对地震波的选取、动力方程数值求解等问题进行了一些讨论和分析。时程分析的结果与实验数据吻合程度基本令人满意,可以作为后续分析的对照依据。在接下来的push-over分析中,为了进一步深入掌握结构的工作机理和进行研究探索,采用了实体模型,即采用空间实体单元模拟的混凝土和空间杆单元模拟的钢筋来构成杆件,并尝试采用温度应力来模拟预应力。这种方式比通常的杆单元模型复杂,但能够较为细致地揭示构件的破坏过程。计算结果与实验和时程分析的对比表明,上述方法在本模型中取得了成功。
The earthquake is one of the most threatening natural disasters to the humanity. As the nation of the most centralized continental earthquake, the intensity and the frequency of earthquake in our country is the first place in globe. For many years, people have devoted to developing and consummating the theory of earthquake resistance and the engineering measure. Along with the progressing of social productive level, several big earthquakes occurred in recent years at the domestic and foreign presented the characteristic of small casualties and high economic loss. On the one hand, this fact tells that the earthquake resistance ability and the correlation discipline has been developed to a high level, at least may guarantee the life safety, on the other hand, also points out the future target is guarantee of property safety, under the premise of life safety. Under such a circumstance, great efforts have been done by governments, organizations and researchers around the world to meet this challenge, performance-based concept was proposed, its basic goal is the predictable seismic performance of engineering construction, the owners and the designers' choice and realization of different performance capability for the various construction projects. The principal realization method of performance-based seismic design (PBSD) is the displacement-based seismic design (DBSD), so, due to the advantage of concise, intuitionistic and informative, the push-over method whose original intention is to establish a fast appraisal way for earthquake resistance performance of structures under major shock, obtained the focus and developments, along with the widely acceptance of PBSD and DBSD in 90's. Several basic issues and the state-of-the-art of PBSD and DBSD, the origin and developing process of push-over method, as well as the commonly used Capacity Spectrum Method (CSM, ATC 40) and the Non-linear Static Procedure (NSP, FEMA 273) and some important parameters were detailed in first chapter.As a seismic performance assesment method without rigorous theoritical foudation, the veracity (feasibility) of push-over procedure basically depends on whether its computational result could be consistent with or approach to other reliable methods. In many kinds of seismic experiments, shaking table test may reflect the dynamic speciality even damage mechanism of structures under the specific earthquake excitation, therefore is widely adopted in engineering practice and research. The results of a model shaking table test is usedin this paper for comparative research of push-over procedure. The test object is a modified prefabricated prestressed concrete skeleton structure (IMS system) which is intend for the modernization reconstruction and improvement of minority civilian dwelling houses in Yunnan Province. Some important researches since the introducion of this system into China in 1977 were briefed in this chapter, and for the purpose of studying the dynamic speciality and seismic capacity of IMS system, a shaking table test of a 1/2.7 scaled model was conducted. Based on the test results, the nonlinear time history dynamic analysis was performed, and a new approach for simulation of nonliear properties of reinforced concrete (RC) beams and columns was attempted, i.e., the moment-curvature relationship of RC rods was calculated firstly by section analysis, then the RC rods were taken as the equivalent homogenization material, and its elasto-plastic stress-strain law was transformed from the moment-curvature relationship in virtue of some assumption, so the restoring force properties of RC rods could be reproduced indirectly. The merit of such a technique is that some general purpose finite element analysis system could be used plumply for RC components. In concert with the analysis of the model, some problems such as the selection of earthquake records, numerical solution of dynamic equations are disscussed and analyzed. The results of time history analysis approximately tally with test datum, so it could be taken as basis for further analysis. In o
作为一种没有严密理论基础的抗震性能评价方法,push-over分析的准确性(可行性)基本上取决于它的计算结果是否能与其它可靠的方法所得到的结果一致或接近。在各种抗震试验中,振动台模型试验可以反映结构在特定地震激励下的动力特性甚至破坏机理,因此被广泛用于工程实践和研究。本文利用一个模型试验的结果,对push-over方法进行了对比研究。结合云南省少数民族民居的现代化结构体系和施工技术改建,试验对象是改进的整体预应力装配式板柱体系(IMS体系)。本文第二章首先介绍了这种结构体系自1977年引入我国以来所进行的主要研究工作,在此基础上为研究IMS体系在动、静力荷载作用下的动力特性及承载能力,进行了缩尺为1/2.7的模型试验。结合试验结果,进行了杆系模型的弹塑性动力时程分析,其中,尝试了一种新的钢筋混凝土构件非线性模型的模拟方法,即先用截面分析的方法得出钢筋混凝土构件的弯矩-曲率关系,然后将钢筋混凝土构件等效为由均质材料构成,通过引入某些假设将弯矩-曲率关系转化为弹塑性应力—应变关系曲线,从而间接地反映出构件的恢复力特性。这种方法的好处在于可以利用一些通用的有限元软件对钢筋混凝土杆件进行非线性分析。结合本模型的需要,对地震波的选取、动力方程数值求解等问题进行了一些讨论和分析。时程分析的结果与实验数据吻合程度基本令人满意,可以作为后续分析的对照依据。在接下来的push-over分析中,为了进一步深入掌握结构的工作机理和进行研究探索,采用了实体模型,即采用空间实体单元模拟的混凝土和空间杆单元模拟的钢筋来构成杆件,并尝试采用温度应力来模拟预应力。这种方式比通常的杆单元模型复杂,但能够较为细致地揭示构件的破坏过程。计算结果与实验和时程分析的对比表明,上述方法在本模型中取得了成功。
The earthquake is one of the most threatening natural disasters to the humanity. As the nation of the most centralized continental earthquake, the intensity and the frequency of earthquake in our country is the first place in globe. For many years, people have devoted to developing and consummating the theory of earthquake resistance and the engineering measure. Along with the progressing of social productive level, several big earthquakes occurred in recent years at the domestic and foreign presented the characteristic of small casualties and high economic loss. On the one hand, this fact tells that the earthquake resistance ability and the correlation discipline has been developed to a high level, at least may guarantee the life safety, on the other hand, also points out the future target is guarantee of property safety, under the premise of life safety. Under such a circumstance, great efforts have been done by governments, organizations and researchers around the world to meet this challenge, performance-based concept was proposed, its basic goal is the predictable seismic performance of engineering construction, the owners and the designers' choice and realization of different performance capability for the various construction projects. The principal realization method of performance-based seismic design (PBSD) is the displacement-based seismic design (DBSD), so, due to the advantage of concise, intuitionistic and informative, the push-over method whose original intention is to establish a fast appraisal way for earthquake resistance performance of structures under major shock, obtained the focus and developments, along with the widely acceptance of PBSD and DBSD in 90's. Several basic issues and the state-of-the-art of PBSD and DBSD, the origin and developing process of push-over method, as well as the commonly used Capacity Spectrum Method (CSM, ATC 40) and the Non-linear Static Procedure (NSP, FEMA 273) and some important parameters were detailed in first chapter.As a seismic performance assesment method without rigorous theoritical foudation, the veracity (feasibility) of push-over procedure basically depends on whether its computational result could be consistent with or approach to other reliable methods. In many kinds of seismic experiments, shaking table test may reflect the dynamic speciality even damage mechanism of structures under the specific earthquake excitation, therefore is widely adopted in engineering practice and research. The results of a model shaking table test is usedin this paper for comparative research of push-over procedure. The test object is a modified prefabricated prestressed concrete skeleton structure (IMS system) which is intend for the modernization reconstruction and improvement of minority civilian dwelling houses in Yunnan Province. Some important researches since the introducion of this system into China in 1977 were briefed in this chapter, and for the purpose of studying the dynamic speciality and seismic capacity of IMS system, a shaking table test of a 1/2.7 scaled model was conducted. Based on the test results, the nonlinear time history dynamic analysis was performed, and a new approach for simulation of nonliear properties of reinforced concrete (RC) beams and columns was attempted, i.e., the moment-curvature relationship of RC rods was calculated firstly by section analysis, then the RC rods were taken as the equivalent homogenization material, and its elasto-plastic stress-strain law was transformed from the moment-curvature relationship in virtue of some assumption, so the restoring force properties of RC rods could be reproduced indirectly. The merit of such a technique is that some general purpose finite element analysis system could be used plumply for RC components. In concert with the analysis of the model, some problems such as the selection of earthquake records, numerical solution of dynamic equations are disscussed and analyzed. The results of time history analysis approximately tally with test datum, so it could be taken as basis for further analysis. In o
引文
[1] 胡聿贤:地震工程学,地震出版社,1988
[2] 中国地震历史资料编辑委员会:中国地震历史资料汇编第一卷
[3] 中华人民共和国国家标准:《建筑抗震设计规范》GB 50011-2001,中国建筑工业出版社,2001
[4] Moehle, J. P., Displacement based design of RC structure, 10th World Conference on Earthquake Engineering(WCEE), Madrid, 19-24 July 1992, Vol. 8 pp4297-4302
[5] Moehle J. P., Displacement-based design of RC structures subjected to earthquakes, Earthquake Spectra, Vol. 8, No. 3, August 1992, pp403-428
[6] Applied Technology Council(ATC): Guidelines and Commentary for Seismic Rehabilitation of Buildings(ATC-33.03), Redwood City, California, 1995
[7] Federal Emergency Management Agency(FEMA): NEHRP Recommended Provisions for Seismic Regulations for New Buildings(FEMA222A-Provisions), 1994 Edition, Washington, D. C., 1995
[8] Federal Emergency Management Agency(FEMA): NEHRP Recommended Provisions for Seismic Regulations for New Buildings(FEMA223A-Commentary), 1994 Edition, Washington, D. C., 1995
[9] SAC Joint Venture: Program to Reduce Hazards in Steel Moment Frame Structures, Topical Reports on Case Study Buildings(SAC-96-02), Sacramento, California, 1995
[10] Structural Engineers Association of California(SEAOC) Vision 2000 Committee: Vision 2000-A Framework for Performance Based Design, Volumes Ⅰ, Ⅱ, Ⅲ, Sacramento, California, 1995
[11] 李应斌,刘伯权,史庆轩:基于结构性能的抗震设计理论研究与展望,地震工程与工程振动,Vol.21,No.4,2001,pp73-79
[12] 钱稼茹,罗文斌:建筑结构基于位移的抗震设计,建筑结构,第31卷第4期,2001,pp3～6
[13] 程耿东,李刚:基于功能的结构抗震设计中的一些问题的探讨,建筑结构学报,Vol.21,No.1,2000,pp5-11
[14] 编制组:建设工程抗震设计导则(送审稿),2003.9
[15] Freeman S. A., J. P. Nicoletti, J. V. Tyrell, Evaluation of Existing Buildings for Seismic Risk-A Case Study of Puget Sound Naval Shipyard Bremerton, Washington, Proceedings of the US National Conference on Earthquake Engineering, EERI, pp113-122, Berkeley, 1975
[16] US Army: Seismic Design Guidelines for Essential Buildings, Department of the Army(TM 5-809-10-1), Navy(NAVFAC P355.1), Air Force(AFM 88-3, Chap. 13, Section A), Washington, D. C., 1986
[17] US Army: Seismic Design Guidelines for Upgrading Existing Buildings, Department of the Army(TM 5-809-10-2), Navy(NAVFAC P355.2), Air Force(AFM 88-3, Chap. 13, Section B), Washington, D. C., 1988
[18] Applied Technology Council(ATC), An Investigation of the Correlation between Earthquake Ground Motion and Building Performance(ATC-10), Redwood City, California, 1982
[19] US Army: Seismic Design for Buildings, Department of the Army(TM 5-809-10), Navy(NAVFAC P355), Air Force(AFM 88-3, Chap. 13), Washington, D. C., 1992
[20] Applied Technology Council(ATC): Seismic Evaluation and Retrofit of Concrete Buildings(ATC-40), Redwood City, California, Report No. SSC 96-01, 1996
[21] Federal Emergency Management Agency(FEMA): NEHRP Guidelines for the Seismic Rehabilitation of Buildings(FEMA-273), Washington, D. C., 1997
[22] Federal Emergency Management Agency(FEMA): NEHRP Commentary on the Guidelines for the Seismic Rehabilitation of Buildings(FEMA-274), Washington, D. C., 1997
[23] Peter Fajfar, Peter Gaspersic: The N2 method for the seismic damage analysis of RC buildings, Earthquake Engineering and Structural Dynamics, Vol. 25, pp31-36 (1996)
[24] 肖明葵,严涛,王耀伟,赖明:弹塑性反应谱研究综述,重庆建筑大学学报,Vol.21,No.5,1999,pp117-121
[25] 种迅,叶献国,吴本华:Pushover分析中侧向力分布形式的影响,《工程力学》增刊 2001,pp298-302
[2] 中国地震历史资料编辑委员会:中国地震历史资料汇编第一卷
[3] 中华人民共和国国家标准:《建筑抗震设计规范》GB 50011-2001,中国建筑工业出版社,2001
[4] Moehle, J. P., Displacement based design of RC structure, 10th World Conference on Earthquake Engineering(WCEE), Madrid, 19-24 July 1992, Vol. 8 pp4297-4302
[5] Moehle J. P., Displacement-based design of RC structures subjected to earthquakes, Earthquake Spectra, Vol. 8, No. 3, August 1992, pp403-428
[6] Applied Technology Council(ATC): Guidelines and Commentary for Seismic Rehabilitation of Buildings(ATC-33.03), Redwood City, California, 1995
[7] Federal Emergency Management Agency(FEMA): NEHRP Recommended Provisions for Seismic Regulations for New Buildings(FEMA222A-Provisions), 1994 Edition, Washington, D. C., 1995
[8] Federal Emergency Management Agency(FEMA): NEHRP Recommended Provisions for Seismic Regulations for New Buildings(FEMA223A-Commentary), 1994 Edition, Washington, D. C., 1995
[9] SAC Joint Venture: Program to Reduce Hazards in Steel Moment Frame Structures, Topical Reports on Case Study Buildings(SAC-96-02), Sacramento, California, 1995
[10] Structural Engineers Association of California(SEAOC) Vision 2000 Committee: Vision 2000-A Framework for Performance Based Design, Volumes Ⅰ, Ⅱ, Ⅲ, Sacramento, California, 1995
[11] 李应斌,刘伯权,史庆轩:基于结构性能的抗震设计理论研究与展望,地震工程与工程振动,Vol.21,No.4,2001,pp73-79
[12] 钱稼茹,罗文斌:建筑结构基于位移的抗震设计,建筑结构,第31卷第4期,2001,pp3～6
[13] 程耿东,李刚:基于功能的结构抗震设计中的一些问题的探讨,建筑结构学报,Vol.21,No.1,2000,pp5-11
[14] 编制组:建设工程抗震设计导则(送审稿),2003.9
[15] Freeman S. A., J. P. Nicoletti, J. V. Tyrell, Evaluation of Existing Buildings for Seismic Risk-A Case Study of Puget Sound Naval Shipyard Bremerton, Washington, Proceedings of the US National Conference on Earthquake Engineering, EERI, pp113-122, Berkeley, 1975
[16] US Army: Seismic Design Guidelines for Essential Buildings, Department of the Army(TM 5-809-10-1), Navy(NAVFAC P355.1), Air Force(AFM 88-3, Chap. 13, Section A), Washington, D. C., 1986
[17] US Army: Seismic Design Guidelines for Upgrading Existing Buildings, Department of the Army(TM 5-809-10-2), Navy(NAVFAC P355.2), Air Force(AFM 88-3, Chap. 13, Section B), Washington, D. C., 1988
[18] Applied Technology Council(ATC), An Investigation of the Correlation between Earthquake Ground Motion and Building Performance(ATC-10), Redwood City, California, 1982
[19] US Army: Seismic Design for Buildings, Department of the Army(TM 5-809-10), Navy(NAVFAC P355), Air Force(AFM 88-3, Chap. 13), Washington, D. C., 1992
[20] Applied Technology Council(ATC): Seismic Evaluation and Retrofit of Concrete Buildings(ATC-40), Redwood City, California, Report No. SSC 96-01, 1996
[21] Federal Emergency Management Agency(FEMA): NEHRP Guidelines for the Seismic Rehabilitation of Buildings(FEMA-273), Washington, D. C., 1997
[22] Federal Emergency Management Agency(FEMA): NEHRP Commentary on the Guidelines for the Seismic Rehabilitation of Buildings(FEMA-274), Washington, D. C., 1997
[23] Peter Fajfar, Peter Gaspersic: The N2 method for the seismic damage analysis of RC buildings, Earthquake Engineering and Structural Dynamics, Vol. 25, pp31-36 (1996)
[24] 肖明葵,严涛,王耀伟,赖明:弹塑性反应谱研究综述,重庆建筑大学学报,Vol.21,No.5,1999,pp117-121
[25] 种迅,叶献国,吴本华:Pushover分析中侧向力分布形式的影响,《工程力学》增刊 2001,pp298-302